My house is a small 2bed, 1 bath with 1 car garage. At some point a previous owner did an unpermitted addition that enclosed the patio off of the back of the garage. It appears to be a pretty well done room, measuring 13’ (width of garage) x 20’ (length of house behind the garage. So the room shares the one 13’ wall with the back of the garage and the one 20’ wall with the old side of the house. The house is on a raised foundation, but the bonus room is not. The bonus room has a door into the garage and a door into the backyard. I want to add a bathroom inside the bonus room to make it a studi. The wall is shared with the bathroom of the house. Will the best bet be to run the drain and pluming through the raised foundation? Will that compromise the foundation?